<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>圣杯布局</title>
</head>
<body>
  <div class="container clearfix">
    <div class="content"></div>
    <div class="left"></div>
    <div class="right"></div>
  </div>
</body>
<style>
  .container {
    /* width: 100%; */
    padding: 0 200px;
    height: 600px;
  }

  .content {
    width: 100%;
    height: 400px;
    background-color: red;
  }

  .left, .right {
    width: 200px;
    height: 300px;
  }

  .container > div {
    float: left;
  }

  .left {
    position: relative;
    margin-left: -100%;
    left: -200px;
    background-color: yellow;
  }

  .right {
    margin-right: -200px;
    background-color: blue;
  }
</style>
</html>